Fluorescent agents



2,709,702 Patented May 31, 1955 FLUORESCENT AGENTS William WilsonWilliams and Harlan B. Freyermuth, 5

Easton, Pa., assignors to General Aniline & Film Cor- Example 2 22 partsof sodium 4,5-diphenylimidazolone disulfonate was dissolved in 500 partsof Water in a two-liter beaker by heating to 5055 C. To this solutionwas added paragon New York a corporal-l of Delaware a solution of 5parts of dicyclohexylamine, 500 parts N0 Drawing. Application October12, 1951, of waterand 91 parts of concentrated sulfuric acid Serial No.251,144 1O (specific gravity 1.84). The white crystalline s'altprecipitated immediately. The mixture was stirred for onea Chums((111260 309'6) half hour and the product was filtered on a Buchner. The

product was washed with 300 parts of Water and then This inventionrelates to novel spirit soluble amine salts dried in a vacuum oven at 85C. Yield: 32.7 parts. of 4,5-diphenylimidazolonedisulfonic acid whichare of This product had the formula:

H2 H2 particular value as fluorescent brightening agents for 5 Both ofthe above products were soluble in ethanol and lacquers, shellac andplastics, particularly vinyl type the solution had a brilliant bluefluorescence under ultraplastics. violet light. They were also solublein acetone but did The novel compounds of the present invention are, asnot fluoresce in this solvent. They were also soluble in stated, spiritsoluble, i. e., soluble in a wide variety of methanol, mineral spirits,benzene, acetone and ethyl volatile organic solvents such as methanol,ethanol, aceacetate but did not fluoresce in ethyl acetate. tone,methylethylketone, low boiling hydrocarbons (petro- Each of thecompounds prepared above were incorleum ether and benzene) esters (ethylacetate, butyl porated in solutions (lacquers) in volatile solvents ofacetate) etc., and it may, therefore, readily be incornitrocellulose,cellulose acetate, ethyl cellulose methyl porated in such compounds aslacquers, shellac and many methylacrylate, vinyl chloride-vinyl acetatecopolymer vinyl type plastics. These compounds fluoresce in the lacquerand shellac so that there was present 0.3% by presence of ultra violetlight with a blue fluorescence so weight of the fluorescent compoundsbased on the solids that when a minor amount thereof is incorporated incontent of the solutions. The thus obtained solutions lacquer or vinyltype plastic which is nearly colorless, the were opaque white and didnot fluoresce in daylight but blue fluorescence of the compoundneutralizes any slight had considerable greenish blue fluorescence underultrayellowishness of the material of which they are incorviolet light.These solutions were coated on sized paper porated with the result thatthe material containing them and it was found that in each case thecoating from the is much whiter or brighter in appearance. They are alsolacquers containing the fluorescent agents of the present useful asultraviolet light filters in lacquers, shellac, or invention were muchwhiter in appearance than the coatvinyl type plastics. ings obtainedfrom similar solutions which contained no The preparation of thecompounds of the present invenfluorescent agent. It was also found thatthe fluorescent tion will be apparent from the following specificexamples: agents of the present invention were-resistant to fading underultraviolet light and the coatings from the above solutions containingthese fluorescent agents showed much less fading under ultraviolet lightwhen exposed in a fadometer than did coatings from like solutionscontaining other fluorescent agents which were exposed along with them.

While the cyclohexyl amine salts and dicyclohexylamine salts of the4,5-diphenylimidazolonedisulfonic acid are particularly preferredfluorescent agents of the present invention, it has been found thatother amine salts of 4,5-diphenylimidazolonedisulfonic acid possesssubstantially similar properties and may be used, if desired. Such saltsare the primary and secondary aliphatic amine salts obtained fromprimary and secondary aliphatic amines containing at least 8 carbonatoms such as dibutyl amine, diamyl amine, octyl amine and dioctylamine. Also the di-o-tolylguanidine salts are substantially equivalentto the cyclohexylamine salts specifically described bove H 0 G H w.

ecla:

Example 1 parts of 4,S-diphenylimidazolonedisulfonic acid was dissolvedin 150 parts water in a l-liter beaker and heated 50 to -7 0 C. 3 partsof activated charcoal (Nuchar) was added and after stirring for about 5minutes, the mixture was filtered through a small Buchner funnel. Thecharcoal cake was washed with about 50 parts of Water. The filtrate (pH0.5) was titrated to pH 11.0 with 16.9 parts 5 cyclohexylamine in al-liter beaker with continual stirring. The product precipitated out atabout the neutral point. The pH was adjusted to 5-6 with a few cc. ofglacial acetic acid. The product was filtered on a Buchner funnel andthe cake was washed with 50 parts of water. The 60 product was dried ina vacuum oven at 6065 C. Yield:

42 parts. This product had the formula EN NH S03E31? 1. Compounds of theformula H 0-H O CH \C/ H 0/ H Oi ?Q A i 5 I NH.HOsS HN\ /NH SOaH.HN\HaC\ i 2 a R1 0 B1 c o 3 Ha Ha 3 2 wherein the groups 3. Thedicyclohexylamine salt of 4,5-diphenylimidazo- R lone disulfonic acid.Reference-a flied in the file of this patent R1 5 UNITED STATES PATENTSrepresent an amino radical selected from the group con- 2,530,234 Lecher25 1951 sisting of monoand dicyclohexylamino radicals, monoanddi-alkylamino radicals containing 8 to 16 alkyl carbon FOREIGN PATENTSatoms, and di-o-tolylguanidino.

2. The cyclohexylamine salt of 4,5-diphenylimidazo- 10 lone disulfonicacid.

7 35,478 Germany May 18, 1943

1. COMPOUNDS OF THE FORMULA